A fluorinated polymer has useful characteristics such as high transparency, low refractive index and low surface tension. A fluorinated polymer composition having the fluorinated polymer dissolved in a specific solvent, is known and has been used as a coating material for various applications. In Patent Document 1, a resin composition for coating is disclosed, which comprises a polymer having a fluorinated aliphatic ring structure having an intrinsic viscosity in a specific range, and a solvent which dissolves the polymer, as essential components.
However, a solvent which is possibly used for dissolving such a polymer described in Patent Document 1, is limited to a special solvent such as a solvent completely fluorinated or a solvent having a perfluoroalkyl group having at least 5 carbon atoms, and such limitation prevented expansion of its application. Further, many of such solvents cause a concern that they tend to function as greenhouse effect gases or a concern that they tend to cause formation of the ozone holes, whereby there was a need for a fluorinated polymer which is soluble in a wide range of fluorinated solvents, and which is suitable as a coating material.
Patent Document 1: JP-A-3-252474